Buggy code:
public final class WorkbenchHelpSystem implements IWorkbenchHelpSystem { public static final String HELP_KEY = "org.eclipse.ui.help" ; private static final String HELP_SYSTEM_EXTENSION_ID = ( ( PlatformUI . PLUGIN_ID ) + '.' ) + ( IWorkbenchRegistryConstants . PL_HELPSUPPORT ) ; private static final String HELP_SYSTEM_CLASS_ATTRIBUTE = "class" ; private static WorkbenchHelpSystem instance ; private static class WorkbenchHelpListener implements HelpListener { public void helpRequested ( HelpEvent event ) { } } private boolean isInitialized ; private AbstractHelpUI pluggableHelpUI = null ; private String desiredHelpSystemId ; private Hashtable registeredIDTable ; private IExtensionChangeHandler handler = new IExtensionChangeHandler ( ) { public void addExtension ( IExtensionTracker tracker , IExtension extension ) { } public void removeExtension ( IExtension source , Object [ ] objects ) { } } ; private class CompatibilityIHelpImplementation implements IHelp { public void displayHelp ( ) { } public void displayContext ( IContext context , int x , int y ) { } public void displayContext ( String contextId , int x , int y ) { } public void displayHelpResource ( String href ) { } public void displayHelpResource ( IHelpResource helpResource ) { } public void displayHelp ( String toc ) { } public void displayHelp ( String toc , String selectedTopic ) { } public void displayHelp ( String contextId , int x , int y ) { } public void displayHelp ( IContext context , int x , int y ) { } public IContext getContext ( String contextId ) { } public IToc [ ] getTocs ( ) { } public boolean isContextHelpDisplayed ( ) { } } private static class ContextWithTitle implements IContext2 { private IContext context ; private String title ; ContextWithTitle ( IContext context , String title ) { } public String getTitle ( ) { } public String getStyledText ( ) { } public String getCategory ( IHelpResource topic ) { } public IHelpResource [ ] getRelatedTopics ( ) { } public String getText ( ) { } } private IHelp helpCompatibilityWrapper = null ; private static HelpListener helpListener ; public String getDesiredHelpSystemId ( ) { } public void setDesiredHelpSystemId ( String desiredHelpSystemId ) { } private WorkbenchHelpSystem ( ) { } public static WorkbenchHelpSystem getInstance ( ) { } public static void disposeIfNecessary ( ) { } public void dispose ( ) { } private AbstractHelpUI getHelpUI ( ) { } private boolean initializePluggableHelpUI ( ) { } private static Point computePopUpLocation ( Display display ) { } private HelpListener getHelpListener ( ) { } public IHelp getHelpSupport ( ) { } public void setHelp ( IAction action , final Object [ ] contexts ) { } public void setHelp ( IAction action , final IContextComputer computer ) { } public void setHelp ( Control control , Object [ ] contexts ) { } public void setHelp ( Control control , IContextComputer computer ) { } public void setHelp ( Menu menu , Object [ ] contexts ) { } public void setHelp ( Menu menu , IContextComputer computer ) { } public void setHelp ( MenuItem item , Object [ ] contexts ) { } public void setHelp ( MenuItem item , IContextComputer computer ) { } public HelpListener createHelpListener ( ICommand command ) { } public void displayHelp ( ) { } public void displaySearch ( ) { } public void displayDynamicHelp ( ) { } public void search ( String expression ) { } public URL resolve ( String href , boolean documentOnly ) { } public void displayContext ( IContext context , int x , int y ) { } public void displayHelpResource ( String href ) { } public void displayHelp ( String contextId ) { } public void displayHelp ( IContext context ) { } public boolean isContextHelpDisplayed ( ) { } public void setHelp ( final IAction action , final String contextId ) { } public void setHelp ( Control control , String contextId ) { } public void setHelp ( Menu menu , String contextId ) { } public void setHelp ( MenuItem item , String contextId ) { } private void setHelpTrace ( String contextId ) { <START_BUG> IllegalArgumentException e = new IllegalArgumentException ( ) ; <END_BUG> StackTraceElement [ ] stackTrace = e . getStackTrace ( ) ; StackTraceElement currentElement = null ; for ( int s = 0 ; s < ( stackTrace . length ) ; s ++ ) { if ( ( stackTrace [ s ] . getMethodName ( ) . equals ( "setHelp" ) ) && ( ( s + 1 ) < ( stackTrace . length ) ) ) { currentElement = stackTrace [ ( s + 1 ) ] ; break ; } } if ( ( registeredIDTable ) == null ) registeredIDTable = new Hashtable ( ) ; if ( ! ( registeredIDTable . containsKey ( contextId ) ) ) registeredIDTable . put ( contextId , currentElement ) ; else if ( ! ( registeredIDTable . get ( contextId ) . equals ( currentElement ) ) ) { StackTraceElement initialElement = ( ( StackTraceElement ) ( registeredIDTable . get ( contextId ) ) ) ; String error = ( ( ( ( ( ( "UI<seq2seq4repair_space>Duplicate<seq2seq4repair_space>Context<seq2seq4repair_space>ID<seq2seq4repair_space>found:<seq2seq4repair_space>'" + contextId ) + "\'\n" ) + "<seq2seq4repair_space>1<seq2seq4repair_space>at<seq2seq4repair_space>" ) + initialElement ) + '\n' ) + "<seq2seq4repair_space>2<seq2seq4repair_space>at<seq2seq4repair_space>" ) + currentElement ; System . out . println ( error ) ; } } public boolean hasHelpUI ( ) { } }

Fix:
RuntimeException e = new RuntimeException ( ) ;